If you’ve ever thought that perhaps the combination of a 5000-plus-pound luxury sedan and hybrid technology seems a bit counterintuitive, we’re with you. Blame CAFE regulations—and blame Lexus. The luxury-car game is a nonstop arms race, with every big-ticket manufacturer rushing to make sure they don’t fall behind in the technology department, and the 2008 LS600hL hybrid could be considered the snowball that started the avalanche that continues with this car, the 2010 BMW ActiveHybrid 7. (Mercedes-Benz is rolling out the S400 BlueHybrid for 2010, too.)

Different but Not That Different

There are two ways to apply hybrid technology. There’s the Toyota Prius way of doing things: make a responsible fuel miser that’s so slow you’d think pedaling would be faster. And then there’s the big-gun luxury way: the BMW ActiveHybrid 7 uses its electric motor to assist a 440-hp twin-turbo V-8 in making “the fastest-accelerating hybrid sedan in the world.” (The blown V-8 produces 400 hp in a nonhybrid 7.) The new hybrid 7 is said to reach 60 mph from a stop in just 4.8 seconds (the Lexus takes 5.4) and top out at an electronically limited 150 mph, all while achieving an estimated 15-percent increase in fuel efficiency over a standard 750i. That efficiency declaration has yet to be verified by the EPA, but the 2009 750i is rated at 15/22 mpg city/highway, so the ActiveHybrid 7 should get around a 17/25 rating if the claim holds true.

While the 7’s hybrid system was co-developed with Mercedes-Benz, the two manufacturers have put it into practice in different ways. The S400 pairs the small, disc-shaped, 20-hp electric motor shared between the companies with its 3.5-liter V-6, while BMW goes all out, hooking the motor to the twin-turbo V-8 to produce a combined 455 hp and 516 lb-ft of torque. The electric motor is found between the engine and torque converter—inside the housing of a new eight-speed automatic transmission—and produces maximum torque of 155 lb-ft compared with 118 lb-ft in the S400. Electric power is stored in a 35-cell lithium-ion battery pack weighing just shy of 60 pounds. Enclosed in a high-strength steel casing located in the trunk floor, BMW says the small battery and its location preserves the 50/50 weight distribution of the 7-series. It also preserves the car’s 13 cubic feet of cargo capacity; trunk space is not encroached on as in the LS600hL, which sacrifices over six cubic feet of cargo capacity to make room for its batteries.

Charging the battery is accomplished through regenerative braking. When the driver is coasting or applying the brake, the electric motor acts as a generator to feed power back into the battery. BMW says the balance between electrical and mechanical braking is seamless and the driver won’t notice a difference from the standard 750i. We’re always dubious of such claims, and we noticed a bit of unnatural pedal feel and nonlinearity in the Mercedes S400 BlueHybrid’s brakes.

More Hybrid-Specific Tech

The ActiveHybrid 7 will be among the first BMWs—along with the new ActiveHybrid X6—to have the company’s auto start/stop function in the U.S. This system turns off the gas engine at stops to save fuel and restarts the engine using the electric motor (the vehicle has no starter) when the driver’s foot comes off the brake or depresses the accelerator.

Beyond not having a starter, the hybrid 7-series also loses the conventional car’s alternator and belt drive for the air-conditioning compressor and hydraulic pump. Instead, the cooling system uses power from the lithium-ion battery, and it can be activated by remote before you enter the vehicle.

Aesthetically, the ActiveHybrid 7 is distinguished through unique badges found on the decklid, C-pillars, and door sills, along with aerodynamically-tuned, ten-spoke, 19-inch alloy wheels. A special Bluewater Metallic paint is also available on regular and extended-wheelbase models. The hybrid 7 will arrive at U.S. dealers in the spring of next year.

The Best and Others to Consider

The Editors' Rating summarizes a vehicle's overall degree of excellence and is determined by our editors, who evaluate hundreds of vehicles every year and consider numerous factors both objective and subjective.

Price Starting at

$90,895

Compare

The S-class has always been synonymous with luxury, and it continues that proud tradition.

The Editors' Rating summarizes a vehicle's overall degree of excellence and is determined by our editors, who evaluate hundreds of vehicles every year and consider numerous factors both objective and subjective.

The Editors' Rating summarizes a vehicle's overall degree of excellence and is determined by our editors, who evaluate hundreds of vehicles every year and consider numerous factors both objective and subjective.

Price Starting at

$116,875

Compare

Brute power and a traditionally unassuming design make the S8 Plus a veritable wolf in sheep’s clothing.